1. Field of the Invention
The invention relates to a methodology and apparatus adapted to capture still images from video sources in real time for the composition of those images.
2. Description of the Prior Art
There exists a need and desire among a wide range of individuals and organizations to capture important, interesting and/or meaningful events for future appreciation, viewing and/or other use. Particularly, there is a longstanding desire among industry and consumers to obtain still images in the form of silver halide photographs or similar hard-copy images of events of various kinds. It will be appreciated by those familiar with the photographic art, that there is considerable difficulty involved in capturing a precisely defining photograph of an event occurring at a single instant in time. The difficulty herein lies both in the photographic composition of the subject matter and in the selection of the precise instant at which to take the picture.
RedHawk Vision Inc. has developed software that generates high quality images from video source material as set forth in U.S. Pat. No. 4,675,532 and copending U.S. patent applications Ser. Nos. 09/697,017 and 09/427,384, which are incorporated herein by reference. This RedHawk software allows a user to select a precise moment captured in video source material, zoom, pan and spatially clip the scene dimensions to a desired format size and then generate a high resolution image by combining information from the selected video frame with information from temporally nearby video frames. The RedHawk software user can 1) choose the precise moment in time; 2) spatially frame the subject matter; and 3) determine the length of time (i.e. number of video frames) over which the “moment” is to be “taken”. Experience with the RedHawk software has shown that particularly compelling pictures that portray individual moments can be obtained from video of the subject activity much more reliably and easily than can similar images made by still photography during the event. We have also found that multiple, different images, derived from a small time segment of a video (e.g. a second or less) may each be particularly compelling. Further, several images of different subjects taken at the same “moment” are also sometimes useful. The result is that the RedHawk software often is used to extract multiple, different images from a single “moment”, all of which images are useful.
Notwithstanding the considerable usefulness and desirable and advantageous characteristics of the current RedHawk software, there remain several limitations and disadvantages associated with its use and with the use of frame-grabbers and similar technologies, techniques, methods and products available from others for extracting still images from video. Among the problems and disadvantages of current still extraction technologies is the effort required to locate the point within the video source from which the image is to be extracted.
On the one hand, simple frame-grabbers such as the Snappy Hardware Frame Grabber allow the user to trigger the “grab” of a video frame in real time, without the need to re-watch the event on tape to find the “moment” of interest. This offers a significant “work flow” advantage, however the technique presents all of the timing difficulties of real-time, still photography. As a practical matter, the user may end up watching an event multiple times by replaying the video or parts thereof, and making multiple attempts to precisely “time” capture of the moment of interest, obviating the work-flow advantage of capturing the event in real-time.
Alternatively, computer based video editing systems and software such as Adobe® Premiere® and specialized stills-from-video systems such as Salient Stills Video Focus™ system require that the video of interest be recorded or input in its entirety before the moment to be extracted as a still image is extracted. Not withstanding that such systems offer precise control of the moment to be extracted as a still image, they all require that the entirety of the video of interest be captured and/or input into the system prior to making the still image, thus substantially increasing the work flow time and effort over systems that allow capture of an image in real time. It is noteworthy that some implementations of the RedHawk software, including those which operate as “plug-in” accessory software to Adobe Premiere exhibit this disadvantage.
A further limitation of present systems that capture still images from video sources is the considerable difficulty that ensues when a user having an extracted still image, either in hard copy form, as for instance in the form of a silver halide print, or in the form of a digital still image file such as a JPEG file; wishes to obtain a slightly different image of the same moment. Current systems for extracting still images from video do not “tag” image files with information identifying the source video file or the location therein from which the still image was obtained. While still image editing software such as Adobe® Photo Shop® allows the addition of meta-data to some still image file formats that permit such meta-data to be included, manually, this may still not allow easy location of the video source material and the location within it to allow creation of related still images.
Video files are naturally large. For instance, an hour of uncompressed video having 640×480 pixel resolution, 24-bit color resolution and 30 frame per second rate requires more than 71 billion bytes of storage. The large size of video files makes their storage “on-line” problematic in many cases and makes it difficult if not impossible to return to the precise moment in a particular video file or tape from which an image was taken to obtain a similar, or related image of the moment of interest. This is particularly a problem if a long time has elapsed between the generation of the initial still image and the need or desire for the subsequent image as the video file may no longer be available on the computer or, in the case of hardware frame grabbers, the original tape may have been lost or discarded.
Thus, it is an object of the invention to permit the capture of still images from video sources in real time with greatly increased precision in the timing and control of the composition of the images.
It is also an object of the present invention to facilitate the creation of related images of a captured moment at a later time.
It is a further objective of the invention to minimize the storage and transmission bandwidth required when obtaining still images from video sources and obtaining hard copy images there from.
A yet further object of the invention is to insure availability of adequate storage capacity on a users system prior to capturing images to prevent failure to capture an image at a critical moment owing to a lack of available storage.
An additional object of the invention is to inhibit the viewing and/or use of captured image information by unauthorized persons.
These and other objects of the invention can now be understood by turning to the following brief summary.